The Momentum from Ryka is a structured cushioning shoe for the runner that needs added medial stability to prevent over pronation. Features include synthetic and mesh upper for lightweight breathable support. Split asymmetrical TPU shank for medial control and lateral flexibility. Asymmetrical rearfoot Ryka Engage insert provides targeted lateral cushioning at point of impact. Forefoot Ryka Engage provides superior cushioning with rebound and removable molded Nitracel sockliner provides added cushioning and comfort.